Facebook has introduced a new way for friends to swap cash with one another that doesn't involve meeting in person, writing a check, or even opening up another app. With Facebook Pay, they can send and receive money directly inside of Messenger. And it won't cost them a thing.

It's no secret Facebook wants users spending as much time on the social network as possible, and this new feature falls right in line with that strategy. Every time you step out of Messenger to open another app—say Google Wallet, PayPal, or Venmo —you stand the risk of getting distracted and doing something else rather than continuing to interact with a Facebook product. This helps alleviate that risk.

As for actually sending money, here are the instructions straight from Facebook. Note that the feature only supports debit cards, as credit cards would introduce fees to the experience that Facebook doesn't want to deal with.

To send money:

Start a message with a friend

Tap the $ icon and enter the amount you want to send

Tap Pay in the top right and add your debit card to send money

To receive money:

Open the conversation from your friend

Tap Add Card in the message and add your debit card to accept money for the first time

After you add a card, Messenger will prompt you to create a PIN. This way friends can't pick up your phone and send themselves money while they're changing your status and swapping your profile picture out for something phallic. Well, not as easily, anyway. When it comes to Facebook, there's no accounting for the human element.